import React from 'react';//核心库
import ReactDOM from 'react-dom';//react dom
import './index.css';
import App from './App';
import reportWebVitals from './reportWebVitals';
import reactDom from 'react-dom';

ReactDOM.render(
  //可以检测不合理的地方
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);
//reactDom.render(<App/>,document.getElementById('root'));和上面效果一样
// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
//上面引入这里使用记录应用性能的
reportWebVitals();
